1. Field of the Invention
The present invention relates generally to an apparatus and method for displaying a picture in a portable terminal, and in particular, to an apparatus and method for displaying a picture, for adjusting a color quality of a picture to guarantee the visibility of an output picture depending on an ambient brightness in a portable terminal.
2. Description of the Related Art
In recent years, portable terminals such as mobile communication terminals or Personal Digital Assistants (PDAs) have become widely used. Portable terminals are increasing, as time goes by, in their number of uses, such as photographing an image or a video through an equipped digital camera, viewing a satellite broadcast, editing a document, playing a game, navigating, listening to music, transmitting/receiving a short message, and transmitting/receiving a multimedia message attached with a photographed image or moving picture, as well as simple telephony or schedule management.
The camera can use a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) sensor. A display unit can use a Liquid Crystal Display (LCD). The miniaturization of cameras leads to a tendency to miniaturize devices containing cameras. Portable terminals can photograph and display video pictures as moving pictures or still pictures. Also, portable terminals can transmit photographed pictures to a base station. The portable terminals are equipped with camera modules for processing high-resolution video data. Thus, portable terminals can process and store high-resolution true color image data at the level of a general digital camera. However, the portable terminal is limited in size and thus, its display unit generally is small in size. Such a small-sized display unit can display a high-resolution true color video, however, a high-resolution true color video has a drawback that visibility, which is the ability of human visual perception, may be rather deteriorated under bright outdoor circumstances, as a resolution increases and the number of expressed colors increases.
In many cases, portable terminals are used mainly outdoors. In a case where an ambient brightness is greater than a brightness of the display unit, there occurs a drawback that visibility deteriorates enough to make it difficult for a user to identify a picture displayed on a display unit of the portable terminal. This drawback worsens due to a limitation in the brightness of a backlight source, in a case where the display unit is a transmissive LCD using only a backlight source.
In order to overcome the drawback, a new light transmission method or light source is under development. However, the real circumstances are that it is difficult to develop a product satisfying consumers even under a strong midday sunshine.
In a case where the drawbacks of visibility reduction appear complex, the reduction of visibility appears more greatly. In other words, visibility is greatly deteriorated when a display unit of a portable terminal displays high-resolution true color video data in a place where ambient brightness is greater than brightness of the display unit.